AuCd合金相变稳定性的理论研究

Theoretical Investigation of Transformation Stability in the AuCd Alloy

摘要:

采用第一原理平面波法，计算AuCd合金中B2、γ2’和ζ2’相的能带结构、晶格参数和总能量，计算结果和实验数据符合得很好。计算结果表明：对于B2、γ2’和ζ2’ 3种不同的结构，能带结构在费米面以下非常相似；费米面以上的能带曲线陡峭，而以下的却很平滑。γ2’相具有最低的系统总能量，稳定顺序依次为γ2’>ζ2’> B2。AuCd合金γ2’相的晶格参数在释放内部应力过程中，总是遵循一个简单规律，即晶格参数a变小，b和c变大。实验测得的这3个晶格参数的变化趋势和本研究计算得到的理论结果完全一致。

Abstract:

A first principles plane-wave method was utilized to investigate the band structure, lattice parameters and total energy for AuCd B2, γ2’ and ζ2’ structures. The results are in good agreement with experimental results. We have found that the band structures for three structures are very similar: steep profile above Fermi level, and flat blow the Fermi level. In the three structures, γ2’ phase holds the lowest energy, and the order of stability is γ2’>ζ2’> B2. AuCd γ2’ structure changes its lattice parameters according to a common principle that is lattice parameter a diminishes and b and c become larger. This result consists with the experimental result.